Ascaris technique

The two-micropipette current-clamp technique for examining the massed responses of ion channels on Ascaris body muscle... 

Fig. 21.2. Two-microelectrode current-clamp technique used to observe, in single Ascaris body muscle cells in a body-flap preparation, the response to a controlled pulsed application of levamisole. One micropipette, to measure membrane potential, and another micropipette, to inject current, are inserted inside the area of the muscle cell known as the bag region. Levamisole is applied in a time- and pressure-controlled manner from a microcatheter placed over the bag region of the muscle. A second microcatheter is used to apply additional chemical agents (Martin, 1982).

Fig. 21.4. Vesicle formation and patch-clamp techniques used to record levamisole receptor channel currents from Ascaris muscle. (A) Muscle membrane vesicles bud-off from the bag membrane following a 10 min collagenase treatment and incubation for 1 h at 37°C in Ascaris saline. (B) Levamisole is applied to the outside surface of the membrane to activate receptor channels cell-attached patches are usually used but it is also possible to make inside-out and outside-out patch recordings.

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